Breakthrough results from the AWAKE project have just been published in the prestigious scientific journal ‘Physical Review Letters’, both of them at “editor’s suggestion”.

Plasma cell in the AWAKE Tunnel (copyright CERN)

The first paper describes experimental evidence for seeded
self-modulation of long bunches of protons in a rubidium plasma, using
time-resolved Optical Transition Radiation (OTR) images taken with a streak
camera, supported by beam core and beam halo images obtained at an imaging
station with a scintillating screen.

The second paper reports on transverse self-modulation in a
proton bunch, seeded by an intense laser pulse which co-propagates with the
protons through a plasma. A linear variation of modulation frequency with
plasma density is also observed, showing that the modulation and the plasma
frequencies are equal, as expected.

These results are key to achieving the goal of using wakefields, created in a plasma and driven by long proton bunches, for accelerating electrons which are injected to follow these wakefields. Ultimately this technique could achieve extremely high accelerations up to hundreds of GeV or even to TeV in short distances, for the benefit of high-energy physics.

Diagram of the AWAKE beam-line (Credits: Edda Gschwendtner, CERN)

AWAKE is the Advanced Wakefield Experiment,
hosted at CERN, which is a collaborative project with significant contributions
from the Cockcroft Institute, through the University of Manchester (pepper-pot
diagnostics for emittance measurement); Lancaster University (RF
synchronisation with the Max Zehnder phase measurement system) and the
University of Liverpool (novel emittance measurement, bunch length measurement
and transverse profile imaging using adaptive optics).

Professor Carsten Welsch from the Cockcroft Institute and
scientific project manager of AWAKE-UK said: “These are fantastic results from the AWAKE
experiment. They open up a pathways for an entirely new technique for particle
beam acceleration which can enable new types of experiments and applications.”